Modification work on high-pressure injection (HPI) pumps at Davis Besse has run into difficulties, further delaying the restart of the reactor.
Following the discovery in March 2002 of boric acid corrosion of the reactor head, operators FirstEnergy reviewed a range of design issues at the plant. Earlier this year FirstEnergy discovered that fine particles that pass through the containment emergency sump could damage the HPI pumps during a loss of coolant accident.
FirstEnergy employed MPR Associates to design and install self-cleaning filters to protect the HPI pumps. During mockup testing, it was discovered that the filter screens were not being properly purged of debris. Further designs are being tested, and FirstEnergy is also considering replacing the pumps instead.
